“For those of you so determined to come up w why my body has changed over the years […] when I started @ 17 I was not yet diagnosed w/Hashimoto’s disease.” (Photo: WENN)

Hashimoto’s disease is one of the most common causes of hypothyroidism, causing inflammation and excessive fluid retention. (Photo: WENN)

Gigi also explained that during the last two years she’s been “properly medicated” to help alleviate the symptoms of the disease. (Photo: WENN)

Gigi says that the changes in her body are due to medication, not her diet, as she says she’s “always eaten the same.” (Photo: WENN)

Three years ago, Hadid wrote an open letter to defend herself against comments that accused her of being “too fat for the industry.” (Photo: WENN)

“I represent a body image that wasn’t accepted in high-fashion before…Yes, I have abs, I have a butt, I have thighs, but I’m not asking for special treatment,” she said in 2015. (Photo: WENN)

In the tweets posted on Sunday, Hadid said she will not further explain the way her body looks. (Photo: WENN)

“Please, as social media users & human beings in general, learn to have more empathy for others,” Hadid wrote. (Photo: WENN)

“Use your energy to lift those that you admire rather than be cruel to those u don’t.” (Photo: WENN)

Gigi Hadid’s weight is yet again a topic of debate on social media. (Photo: WENN)

Gigi Hadid at New York Fashion Week has become a topic of debate on social media—not because she’s walked in the runway for designers like Jeremy Scott, Bottega Beneta, and Brandom Baxwell, but because of speculations about her extreme weight loss.

After multiple messages swirling around the internet accused the 23-year-old model of being involved with drugs and eating disorders, the eldest Hadid sister took to Twitter to clarify the real reason of her current thinness in a series of tweets shared on Sunday afternoon.

“For those of you so determined to come up w why my body has changed over the years, you may not know that when I started @ 17 I was not yet diagnosed w/Hashimoto’s disease” Hadid explained on a first tweet.

Hashimoto’s disease, the most common form of thyroiditis, is a condition that affects the immune system resulting in a decrease of thyroid activity, causing “inflammation and excessive fluid retention,” as explained by Hadid herself.

Gigi also said that over the past two years, she has been “properly medicated to help symptoms,” which is why her body has changed so much in such a short time, even when she’s “always eaten the same.”

Hadid added: “I will no further explain the way my body looks, just as anyone, with a body type that doesn’t suit ur ‘beauty’ expectation, shouldn’t have to.”

Lastly, Hadid used the occasion to send a message against cruelty in social media. “Please, as social media users & human beings in general, learn to have more empathy for others and know that you never really know the whole story. Use your energy to lift those that you admire rather than be cruel to those u don’t.”